The scanning tunneling microscope (STM) probes the electronic properties of condensed-matter systems by smoothly injecting or removing electrons. Assuming that the machine does not perturb the system, the electronic structure seen by propagating an electron or a hole is exactly what the spectral function does. In other words, the STM reads the spectral function of real systems. The line of research in this group is to develop computational schemes to unveil all the richness of realistic spectral functions. The group is thus interested in electronic, vibrational and magnetic excitations. The Kondo effect is an unavoidable phenomenon of systems that present time-reversal symmetry and electron scattering. Particle pairing like in superconductors is also very exciting. Trying to understand the many different systems and yield quantitative explanations for the several experimental data obtained in STM laboratories around the globe is also this group’s goal.